In the above technical field, patent literature 1 discloses a cancel button configured to cancel lock by a manual pulse generator.
Patent literature 2 discloses an enable and deadman switch in a handy pendant. This switch is a switch having both the function of an enable switch that selects an operation state or a non-operation state of a handy pendant and the function of a deadman switch that immediately stops the movement of a movable body of a machine tool in case of emergency without considering the relationship with set axial data. That is, the enable and deadman switch has stop positions of two steps. For example, when the enable and deadman switch is lightly pressed, the operation state of the handy pendant is formed. In this state, selection of a drive axis, setting of a drive pulse generation rate, and an operation of each drive axis, and the like can be done. On the other hand, when the enable and deadman switch is, for example, strongly pressed up to the secondary stop position, a non-operation state is attained, in which the movement of a movable body of a machine tool immediately stops without considering the relationship with coordinate data. Note that the non-operation state is also attained in a case in which the operator does not touch the enable and deadman switch at all. Hence, selection of a drive axis, switching of a drive pulse rate, and the like can be performed only in the operation state obtained by lightly pressing the enable and deadman switch up to the primary stop position.
In addition, patent literature 3 discloses an NC apparatus including a main operation unit with a screen, and a sub operation unit that displays at least part of the displayed screen and is communicable with the main operation unit and mechanically detachable from the main operation unit.